This application is submitted as a renewal of an existing project grant for the study of clinical hypertension. The studies described in this proposal are designed to assess the interaction of adrenal mineralocorticoid action, the renin-angiotension system and the sympathetic nervous system. Emphasis is place upon measurement of plasma hormones, (plasma renin activity, aldosterone and catecholaaines) and comparison with the hemodynamic effects of specific pharmacologic blockade employing spironolactone, saralasin and alpha- and beta-adrenergic receptor antagonists. Thus, the compensations in the renin-angiotensin system and the sympathetic nervous system to inhibition of mineralocorticoid action to chronic diuretic use will be quantified in various forms of clinical hypertension.